Musical instrument



March 10. 1925. 1,529,306 E. c. HANSON MUSICAL INSTRUMENT Filed March 27, 1920 2 sheets-sheet 1 March 10. 1925.

E. C. HANSON MUSICAL INSTRUMENT Filed March 2'7, 1920 2 Sheets-Shet z Patented Man lO, 1925. I 4 i UNITED STATES PATENT OFFICE.

EARL: C. HANSON, WASHINGTON, DISTRICT OF COLUMBIA. MUSICAL INSTRUMENT. Application filed March 27, 1920. Serial No. 369,334.

To all whom it may concern: tained in case 9. The storage battery 11 Be it known that I, EARL C. HANSON, 21 supplies the current for the microphone cir-' citizen of the United States, residing at cuit. The amplifier 9 derives energy for its ashington, District of Columbia, have inoperation from motor generator set 10 and vented certain new and useful Improvements terminals 12 adapted for connection with any in Musical Instruments, of which the folsuitable source. The output circuit of the lowing is a specification. amplifier is connected to any suitable type My invention relates to instruments for of loud speaker telephone 8. The loud the production of music and more particuf speaker is arranged to concentrate the sound "5 larly to electrical apparatus whereby the invibrations through the amplifying horn 7 tensity of the music'is greatly augmented from which the music is directed from the to be distributed over large areas such as cabinet. Y auditoriums, ball rooms,- motion picture In Figure 2 the amplifier is shown as com: theatres and open air resorts. prising two stages of audio frequency ampli-. To The object of my invention is to provide fication. The vacuum tube 14 has its "filaa unit piece of musical apparatus differing ment suppliedwith energy from alternating in no external appearances from standard current mains 12 through step down transinstruments and yet equipped with electrical former 18. The low potential end of the apparatus to greatly increase h intensity grid circuitof vacuum tube 14 is negatively of the music produced. biased by battery-17 connected between the Another object of the, invention is to proe d fof transformer 13 and the mid vide a unit piece of musical apparatus with point of the secondary windingpf transelectrical equipment included therein and f m r 18, Tran form r 15 i int rpo ed 7 adapted to be operated by connection wi h in the output circuit of the vacuum tube 14 the usual source of house lighting current. d th i ut i it, f vacuum t be 16,

In lieu of this however a small storage bat- Th t b 16 has its filament also supplied tery installation may be employed. from the secondary of transformer 18 and The invention is particularly adapted for has a negatively biased grid from battery phonographs to render the music produced source 17. The plate circuits of each of the y by such machines of audlblll y v l nt tubes are supplied with direct current from to orchestral music. The machine t erefore otor nerator 10. The generator has its can be substituted fOI orchestras Of a numnegative terminal connected to a, ariable ber of pieces and the same effects and volume contactor of resist-41110319 bridged across of music produced as now rende d by the secondary circuit of transformer 18. orchestras in ball rooms, .auditorlums and Th itive terminal of the generator is other amusement places.- wired to complete the plate circuits supply Reference is had to the accompanying. through the primary winding of transdrawings forming part of this applicatlon former 15 and through the loud speaker 8 in which arranged in the output circuit of vacuum Figure 1 is a cross sectional view of a tube 16. phonograph containing within the usual The operation of the apparatus willbecabinet the electrical equipment. readily understood. The sound vibrations Figure 2 is a diagrammatic view showing from sound box 4 are converted into electhe wiring of the apparatus within the trical energy to t e primary circuit of, 1m phonograph cabinet. transformer 13; said energy is amplified Referring to- Figure 1 reference numeral through the agency of the vacuum tubes 14 1 indicates a phonograph cabinet having the and 16. The load speaking telephone 8 is driving mechanism 2 for rotating the record actuated by this greatly amplified energy table 3. The usual sound box 4 is arranged producing the required volume of sound. 11:; for relative motion over the record and has What I claim and desire to secure by Letits tone arm terminating in the telephone ters Patent 1s: I microphone'transmitter 5 suitably supported In a phonograph the combination of a I as indicated at 6. The telephone transcabinet, means therein for producing music, mitter 5 is electrically connected in circuit means, including a telephone microphone 11.: g with the input side of the thermionic vactransmitter, for converting the musical uum tube power amplifier indicated'as con vibrations into variations of electrical energy, a transionn'er therein haying a plying en ergyto the filaments ofeaid vacprimary and secondary winding, 'a theruuni-tube amplifier, adirect current genermo-nic vacuum tubeamplifier therein, the ator therein for energizing the plate circuits primary circuit of said transformer being ofsaid 'vacuum tube amplifier and a loud 5 energize d by said 'variations of electricaF speakr arrang ed within' sai d cabinet in the energy, the secondary winding being assg output circuit of the amplifier for reconciated with the input circuit of said-vac verting'the electrica1 variations into music uurn tubeamplifier, a pair of terminals .fori atvgreatlyincreased volume. connection to a source of alternating cur- [0 rent, a second transfomnertherein jor sup EAR-L C. HANSON. 

